S

Our Drinking Water

Where is it coming from??

Where Chicago Gets its Water

Lake Michigan supplies our water The city takes up to 2.1 billion

gallons of water a day!!

A variety of steps and chemicals are used to make sure our water is safe to drink

The Process

http://youtu.be/LilHhkwdfKM

Take notes on your handout as the video progresses.

Some of the Details

The Process

1. Water from Lake Michigan enters the intake crib at depths of 20 to 30 feet.

2. Water enters the purification plant's intake basin through a tunnel beneath the lake bed.

3. Water is filtered through eight traveling screens to catch debris.

4. Water is pumped by low lift pumps up to 25 feet for the first chemical treatment.

5. Water flows from the chemical application channels..

The Process

6. Water flows through mixing basins to begin the flocculation process.

7. Flocculated water passes into settling basins to sit for hours allowing floc to settle.

8. Water is filtered through precisely graded sand and gravel performing a "natural polishing".

9. Filtered water flows into clearwells for its final chemical application.

10. From finished water reservoirs water flows to the distribution system

The Chemicals in the Process

Very Very Very small amounts are used For every 100 gallons only a teaspoon full of

chemicals is used

There are 5 main chemicals that are used at various times in this process.

Chemicals in the Process

Chlorine - Used to disinfect the water

Alum OR Aluminum Sulfate – To help with coagulation and to settle impurities

Blended Polyphosphate – Coats the pipes to prevent lead contamination

Activated Carbon – Removes unpleasant odors and tastes

Fluoride - Cavity protection for children’s teeth

Sometimes the process doesn’t work

It is rare that there are issues here in the U.S.

To be effective testing and re-evaluation of the system has to happen often.

We will talk about a few times that the system failed

Many of these issues could be prevented by better management of our water at its source

1993- Milwaukee, WI Criptosporidium contamination

What is criptosporidium? It is a protozoan

(single celled organism)

It causes severe diarrhea in people who consume them

1993- Milwaukee, WI Criptosporidium contamination

Where does it come from? It’s a water borne pathogen Typically carried in the feces of both wild

and domestic animals Cannot be killed through chlorination It must be FILTERED out of the water

1993- Milwaukee, WI Criptosporidium contamination

This was the largest and most devastating waterborne disease outbreak in U.S. history

400,000 people were affected (25% of the population of Milwaukee)

As many as 100 individuals died from this exposure

1993- Milwaukee, WI Criptosporidium contamination

Led to improvements and understanding of watershed management Wisconsin does not have an over-abundance of

wildlife But it does have a large number of farms and

domestic livestock Run-off from farms into Lake MI and it’s watersheds

most likely caused the increase in cryptosporidium oocysts

Improvements in water filtration and purification processes

2014 – Lake Erie Algal Bloom

Some species of algae can give off a harmful neurotoxin

Symptoms Nerve damage Liver damage Can cause death if untreated – especially in younger

children or pets

Cannot be treated by traditional water treatment processes

2014 – Lake Erie Algal Bloom

What causes Algal blooms? Run-off from homes and farms Increased levels of Phosphorus and

Nitrogen which are used in fertilizers.

http://www.accuweather.com/en/weather-news/lake-erie-suffering-from-harmf/31210317

What is the theme?

What similarity did the two situations have to each other?

Why do we need to be aware of what we put into our water?

Raise you hand if you have ever dumped something down the sewer in the city OR dropped trash on the street without thinking about it.